An ultrasonic imaging apparatus transmits an ultrasonic wave generated by an ultrasonic transducer in an ultrasonic probe into a patient, receives a reflective wave produced according to difference of sound impedance of a tissue of the patient with the ultrasonic transducer, and displays an image on a monitor. Since a 2-dimensional image data is easily obtained in real time by easy operation of contacting the ultrasonic probe for a body surface of the patient, this imaging method is widely used for functional diagnosis or morphological diagnosis of internal organs, such as a heart.
The ultrasonic imaging method in which living body information is obtained according to the reflective wave from the tissue or blood cell of the patient is developed by two big technical developments of an ultrasonic pulse reflective method and an ultrasonic Doppler method, and B-mode image data and Color Doppler image data which are obtained the above methods, respectively, are very important for the ultrasonic imaging.
In the ultrasonic imaging method, a method for synchronizing the above image data obtained by the transmission-and-reception wave of the ultrasonic wave to the patient with biomedical signal, such as electro cardiographic wave (ECG signal) to display the imaged data and the biomedical signal is conventionally used. Especially, it is useful that the image data and the biomedical signal are displayed simultaneously for seeing a timing of the image data in a cardiovascular diagnosis, for example.
However, it is difficult that the B mode image data or the Colored Doppler image data is displayed with the ECG signal simultaneously, since it takes longer to make the 2-dimensional image data than to make the ECG signal.
In order to solve such a problem, a method in which the image data and the ECG signal are synchronized by delaying the ECG signal is disclosed in Japanese Patent Disclosure (Kokai) No. 3-90141.
As a method for synchronizing medical information obtained from a plurality of medical apparatuses which are connected via a network, Japanese Patent Disclosure (Kokai) No. 11-7428 discloses that internal clocks, each of which is located in the each medical apparatus, are corrected according to a standard time information of a standard clock equipment connected to each apparatus via the network.
However, in the method disclosed in Japanese Patent Disclosure (Kokai) No. 3-90141, rough time for making the image data is presumed, the ECG signal is delayed for the rough time, and therefore, sufficient synchronous accuracy is not acquired. Furthermore, this method is for correcting the delay time of the image data to the ECG signal in a predetermined procedure, and it is based on the premise that the image data and the ECG signal are made and displayed in real time. In the method disclosed in Japanese Patent Disclosure (Kokai) No. 11-7428, the synchronous correction is performed to the medical information of the image data which is already made.
By the way, in a recent ultrasonic imaging apparatus, it is known that ultrasonic data which is an unit of data in each scanning direction used for generation of image data, the unit of data hereinafter called RAW data, is temporally stored in a memory in the apparatus and some days later, various signal processes are performed to the RAW data to make desired image data or analysis data. According to this method, it is possible to perform the signal processing to the RAW data anytime without the patient.
Thus, a conventional example using the RAW data is shown below. FIG. 1 is a block diagram showing a conventional ultrasonic imaging apparatus, FIG. 2 shows a composition of the RAW data stored in RAW data memory 1302, and FIG. 3 is a flow charts of operation of the ultrasonic imaging apparatus.
An ultrasonic imaging apparatus 1100 shown in FIG. 1 includes an ultrasonic probe 1201 which performs transmission-and-reception of ultrasonic wave to and from a patient, a transceiver part 1200 which performs transmission of a drive signal and reception of a reflective signal to and from the ultrasonic probe 1201, and a RAW data generation part 1250 which performs signal processing to the received signal of the transceiver part 1200 to generate RAW data, such as B-mode RAW data, I/Q signal and Color Doppler RAW data. Furthermore, the ultrasonic imaging apparatus 1100 includes a time information addition part 1301 which adds time information supplied from a time information generation part 1312 to the RAW data, and a RAW data memory part 1302 which stores the RAW data, with which the time information is added, per a scanning direction (raster).
Moreover, the ultrasonic imaging apparatus includes a biomedical signal measurement part 1311 which collects a biomedical signal, such as an ECG signal, from the patient, a time information generation part 1312 which generates time information using the biomedical signal, a biomedical signal memory part 1313 which matches and stores the biomedical signal and the time information, and an image data/analysis data generation part 1300 which reads two or more RAW data and generates the image data or the analysis data in a predetermined timing of the biomedical signal based on the time information among the RAW data stored in the RAW data memory part 1302. The ultrasonic imaging apparatus further includes a display data generation part 1305 which combines the image data or the analysis data with the biomedical signal in the predetermined timing and generates display data, a display part 1306 which displays the display data, an input part 1307 which is used for selecting an image data generation mode and for inputting various command signals, and a system control part 1308 which totally controls each above-mentioned part.
The time information addition part 1301 adds the time information (synchronized signal) which is generated based on the biomedical signal of the patient by the time information generation part 1312 to each RAW data, in the scanning direction, generated by the RAW data generation part 1250. The RAW data memory part 1302 sequentially stores the RAW data with which the time information is added.
FIG. 2 shows the composition of the RAW data stored in the RAW data memory part 1302. An vertical axis corresponds to an arrangement of the RAW data of the scanning directions θ1 to θM, and a horizontal axis corresponds to the scanning direction of the ultrasonic transmission-and-reception wave. For example, in M RAW data B-1 to B-M used for making B-mode image data of one frame, pixels a11 to a1L of RAW data B-1, each of which being 12 bits, are generated by the ultrasonic transmission-and-reception in the first scanning direction θ1. A header of the L pixels includes a time information storage area a10a in which the time information is added and a scanning information storage area a10b in which the information about the scanning directional is stored.
Similarly, headers of the RAW data B-2 to B-M in the second scanning direction θ2 to the Mth scanning direction θM include the time information storage area a20a to aM0a, the scanning information storage area a20b or aM0b, and the RAW data pixels storage area for the B mode image am1 to amL (m=2 to M).
In the RAW data memory part 1302, after scanning the RAW data B-1 to B-M in the Mth scanning direction, the RAW data B-1 to B-M for the next B-mode are stored, repeatedly.
And “1” is added to the time information storage area a30a of the RAW data (for example, RAW data B-3) obtained when an R-wave in the ECG signal of the patient is measured, and “0” is added to other time information storage areas.
The biomedical signal measurement part 1311 of FIG. 1 measures the ECG signal from the patient, and the measured biomedical signal is changed into a digital signal by an A/D converter. The time information generation part 1312 has a function for generating the time information (synchronized signal), and for example, when the biomedical signal is the ECG signal, the time information generation part 1312 detects the timing of the R-wave in the ECG signal.
The biomedical signal memory part 1313 matches and stores the biomedical signal supplied from the biomedical signal measurement part 1311 and the time information which the time information generation part 1312 generates based on the biomedical signal.
The image data/analysis data generation part 1300 reads out one or more RAW data in a predetermined timing among the RAW data stored in the RAW data memory part 1302, performs data processing to the read out RAW data, and executes a scan conversion to make the image data.
This image data/analysis data generation part 1300 includes a RAW data processing part 1303 and an image data generation part 1304. The RAW data processing part 1303 reads out the RAW data in the predetermined timing based on the time information added to the RAW data, and performs data processing, such as image processing or analyzing of the RAW data for the B-mode image or the Color Doppler image and spectrum analyzing of the I/Q signal. The image data generation part 1304 performs the scan conversion of the B-mode RAW data or the Color Doppler RAW data which are read out by the RAW data processing part 1303 to make the image data.
The display data generation part 1305 includes an operation circuit and a memory circuit, and the operation circuit reads the biomedical signal in the same timing as the image data supplied from the image data generation part 1304 of the image data/analysis data generation part 1300 or the analysis data supplied from the RAW data processing part 1303. Subsequently, the display data generation part 1305 generates the display data by combining the image data or the analysis data supplied from the image data/analysis data generation part 1300 with the biomedical signal, and temporally stores the display data in the memory circuit.
The display part 1306 includes a conversion circuit and a monitor. In the conversion circuit, D/A conversion and television format conversion execute to the display data generated in the display data generation part 1305, and the converted data is displayed on the monitor, such as CRT or Liquid Crystal Display.
The input part 1307 includes an input device, such as a keyboard, a trackball and a mouse, and a display panel on a navigational panel. An input of patient information or various command signals, selection of image data generation mode, etc. are performed using the input device and the display panel.
Moreover, the system control part 1308 includes a CPU and a memory circuit, and various kinds of inputted information and selection information, etc. which are supplied from the input part 1307 are stored in the memory circuit. The CPU controls each part of a whole apparatus, such as the transceiver part 1200, the RAW data generation part 1250, the time information addition part 1301, the image data/analysis data generation part 1300, the display data generation part 1305, and the display part 1306.
Next, an basic operation of the ultrasonic imaging apparatus 100 and a flow of a synchronous display of the image data and biomedical signal which are obtained by the ultrasonic imaging apparatus 1100 are explained in FIG. 1 through FIG. 3. It is explained below in FIG. 3 that B-mode image data generated from the B-mode RAW data obtained by the ultrasonic transmission-reception to and from the patient and the ECG signal obtained in parallel to the ultrasonic transmission-reception are displayed synchronously.
Before the ultrasonic wave is transmitted and received to and from the patient, a doctor or a sonography technologist (hereafter called an operator) sets electrodes of the biomedical signal measurement part (electrocardiograph) 1311 at a predetermined position of the patient. Next, the operator inputs the patient information or selects the image data generation mode, such as B-mode image data with the input device of the input part 1307, and sets a tip part of the ultrasonic probe 1201 at a predetermined position of the patient (Step S1 of FIG. 3). At this time, the inputted or selected information is stored in the memory circuit of the system control part 1308.
After the initial setting is completed, the transmission and reception of the ultrasonic pulse are performed to and from the patient, based on control of the system control part 1308. The received ultrasonic signal is sent to the B-mode signal generation part of the RAW data generation part 1250.
The B-mode signal generation part executes an envelope detection, logarithm conversion and A/D conversion to the inputted data to generate B-mode RAW data to be supplied to the time information addition part 1301. The B-mode RAW data, as shown in FIG. 2, includes pixels a11 to a1L and a header, amplitude of the A/D converted signal is stored in the pixels a11 to a1L as 12 bits data, and information about the first scanning direction (θ1) is stored in the scanning information storage area a 10b of the header (Step S2 of FIG. 3).
On the other hand, in parallel to the ultrasonic transmission-and-reception in the first scanning direction (θ1), the biomedical signal measurement part 1311 measures the ECG signal of the patient (Step S3 of FIG. 3), and the acquired ECG signal is supplied to the time information generation part 1312. The time information generation part 1312 which receives the ECG signal determines whether the timing of the ultrasonic transmission-and-reception corresponds to the R-wave of the ECG signal, generates the time information based on the determination, and sends the time information to the time information addition part 1301 and the biomedical signal memory part 1313. (Step S4 of FIG. 3).
Subsequently, the time information addition part 1301 adds the time information supplied from the time information generation part 1312 to the time information storage area a10a of the B-mode RAW data (B-mode RAW data B-1 in FIG. 2) in the first scanning direction supplied from the B-mode data generation part 1204 of the RAW data generation part 1250 (Step S5 of FIG. 3). In this case, when the timing of the ultrasonic transmission-and-reception does not corresponds to the R-wave of the ECG signal, as shown in FIG. 2, the time information “0” is added to the time information storage area a10a of the RAW data B-1. Otherwise, the time information “1” is added. The B-mode RAW data with which the time information is added is stored in the RAW data memory part 1302 (Step S6 of FIG. 3).
The time information is added to the ECG signal data supplied to the biomedical signal memory part 1313, and the ECG signal data is stored. (Steps S7 and S8 of FIG. 3).
Similarly, the system control part 1308 performs the ultrasonic transmission-and-reception also in the second scanning direction through the Mth scanning direction, and after the Mth scanning direction, the ultrasonic transmission-and-reception is performed in the first scanning direction through Mth scanning direction repeatedly. Each B-mode RAW data, obtained at this time, with which the time information is added in the time information addition part 1301 is stored in the RAW data memory part 1302, and the ECG signal obtained in parallel to the generating or the storing of the B-mode RAW data with which the time information is added is stored in the biomedical signal memory part 1313.
The RAW data processing part 1303 of the image data/analysis data generation part 1300 confirms the time information of the RAW data B-1, B-2, etc. which are stored in the RAW data memory part 1302 in FIG. 2. When the time information “1” indicating the R wave of the ECG signal is confirmed in the RAW data B-3, for example, RAW data is read out one by one on the basis of the RAW data B-3. Subsequently, the RAW data processing part 1303 performs image processing to the read out RAW data, and supplies the RAW data to the image data generation part 1304.
The image data generation part 1304 performs the scanning conversion to one frame of the B-mode RAW data, in a predetermined timing, which is read out by the RAW data processing part 1303, and generates one frame of the B-mode image data (Step S9 of FIG. 3).
The display data generation part 1305 reads out a series of the ECG signal one by one on the basis of the ECG signal (R-wave) with which the time information “1” is added among the ECG signal stored in the biomedical signal memory part 1313 where the time information is added (Step S10 of FIG. 3). And the display data generation part 1305 combines the B-mode image data supplied from the image data generation part 1304 of the image data/analysis data generation part 1300 with the R-wave of the ECG signal such that the timing of display of the B-mode image data in the third direction θ3 is synchronized with the timing of display of the R-wave of the ECG signal and generates display data.
The display part 1306 executes the D/A conversion, the television format conversion to the display data generated in the display data generation part 1305, generates a display signal and displays the display signal on the monitor (Step S11 of FIG. 3).
According to the above mentioned conventional example, the accuracy may be low since the time information is obtained from the ECG signal, or a large memory space in the header may be required, since the time information is added to the header of the RAW data.